       (make-dataset new-columns
                     new-data))))
 
-(defn drop-rows [dataset n]
+(defn drop-rows
   "Drops the first n rows from the CSV."
+  [dataset n]
   (map-rows dataset (partial drop n)))
 
-(defn take-rows [dataset n]
+(defn take-rows
   "Drops the first n rows from the CSV."
+  [dataset n]
   (map-rows dataset (partial take n)))
 
 (defn derive-column

                             (map first))]
    not-found-items))

(defn all-columns [dataset cols]
  "Takes a dataset and any number of integers corresponding to column
  numbers and returns a dataset containing only those columns.



  One advantage of this over using columns is that you can duplicate
  an arbitrary number of columns."
 [dataset cols]
  (let [not-found-items (invalid-column-keys cols dataset)]
    (if (and (empty? not-found-items)
            (some identity cols))
